Teak deck install... West System on gel coat?

My boss is having me install a decent sized teak deck (about 16'x16') on top of gel coat with no fasteners. The deck overhangs about 12'. If I jump up and down on the aft part of the deck, it feels like a diving board. It springs at least a couple of inches. There is a davit, a couple of runabouts, and a shore boat located on this deck, and I'm sure something heavy will be dropped on it at some point.
I'm scuffing the gel coat with 24 grit paper and a ******* file to try to give the epoxy as much grab as possible, but I'm still not very confident.
I thoroughly clean both surfaces with acetone before installation.

My question is, is this a sound construction technique?
How could I make this a better install?

 

What you are doing is quite OK (as far as laying the twak decking down).
As ti the construction, what can you do about it anyhow, it is already built. It sounds like the depth of the aft deckin too narrow, aft decks are quite deep in profile usually to gain the beam effect of the broader space. On say a 50 foo boat , the aft overhanging deck would be at least 9" deep. The teak decking epoxy glued down will increase thhe strength of the deck marginally, just make sure that your boss does not put a very heavy dinghy off that davit too far aft.

If building fron new, the design would have allowed for a certain amount of weight aft calculation, all that you can sensibly do now is to put stainless steel posts under the overhanging deck area and support them onto the lower deck coaming areas. Two posts, port and stb in the aft corners look quite OK and will make a great difference to the spring that you are talking about.